Postfix/X-Envelope-To

[Andreas John <lists@aj.net-lab.net>]

Hello All!

I wondering is someone knows how to add an X-Envelope-To header to all 
incoming e-mails which reveal the "real" username even when working with 
virtuals.

I tried several apoaches like:
---
# cat /etc/procmailrc
ENV_TO=$1

:0f
* ENV_TO ?? .
| formail -i "X-Envelope-To: $ENV_TO"

:0fE
| formail -i "X-Envelope-To: UNKNOWN OR CATCHALL"
---
The header modification is done well, but the this stage of delivery 
ENV_TO=$1 does not reveal the real username.

RTFG shows me that this problem exists with many MTA (although exim 
seems to have a single line config option for that)

Does anybody know a solution?

rgds,
Andreas